1. Field of the Invention
The instant invention relates to a gathering shoe arrangement for a continuous glass fiber forming operation.
2. Technical Considerations and Prior Art
Glass fibers are commonly formed by attenuating molten glass through orifices in a bushing. The fibers are then drawn across an applicator, which coats at least a portion of the fiber surface with a sizing composition. The coated fibers are then gathered into one or more discrete strands by gathering shoes and wound on a winding machine into a forming package. As a result of the glass fibers being drawn across the gathering shoes to form the strands, and in particular the friction developed between the fibers and the gathering shoes as the fibers contact the shoe, tension is added to the fibers. This additional tension in the fibers can result in degradation of the glass fibers as well as increased fiber breakage during the fiber forming and winding operation. Conversely, if tension can be reduced, the quality of the glass fiber product will improve.
The following patents disclose modified gathering shoe configurations.
U.S. Pat. No. 3,999,970 discloses a gathering shoe configured to reduce the wear of the shoe. The gathering shoe is formed from porous material, such as graphite. A gaseous fluid is introduced into a central cavity within the shoe and forced through slots in the porous material to the surface of the shoe such that the glass fiber strands formed by the shoe ride on a gaseous fluid cushion.
U.S. Pat. No. 4,526,598 discloses a gathering shoe which reduces the wrapping of fibers and/or strands around the shoe. The gathering shoe has an annular groove about its periphery. The groove includes plurality of holes radiating from the groove surface inward toward the center of the shoe.
It would be advantageous to reduce the tension in the fibers so as to improve the quality of the glass fiber strands.